Confluence/Jira roles: add READMEs, switch to custom images, proxy/JVM envs, and integer-safe heap sizing

Confluence: README added; demo disables OIDC/LDAP; Dockerfile overlay; docker-compose now uses CONFLUENCE_CUSTOM_IMAGE and DB depends include; env.j2 adds ATL_* and JVM_*; vars use integer math (//) for Xmx/Xms and expose CUSTOM_IMAGE.

Jira: initial role skeleton with README, config/meta/tasks; Dockerfile overlay; docker-compose using JIRA_CUSTOM_IMAGE and DB depends include; env.j2 with proxy + JVM envs; vars with integer-safe memory sizing.

Context: https://chatgpt.com/share/68b6b592-2250-800f-b68e-b37ae98dbe70

roles/web-app-jira/config/main.yml

@@ -0,0 +1,29 @@
+
+credentials: {}
+docker:
+  services:
+    database:
+      enabled:  true
+    application:
+      image:    atlassian/jira-software
+      version:  latest
+      name:     jira
+  volumes:
+    data:       "jira_data"
+features:
+  matomo:           true
+  css:              true
+  desktop:          true
+  central_database: true
+  logout:           true
+  oidc:             false  # Not enabled for demo version
+  ldap:             false  # Not enabled for demo version
+server:
+  csp:
+    whitelist:      {}
+    flags:          {}
+  domains:
+    canonical:
+      - "jira.{{ PRIMARY_DOMAIN }}"
+rbac:
+  roles: {}